Food for Thought : Sponsored Feed Trial

Each year we carry out a sponsored feed trial in collaboration with our feed manufacturer Coppens International. We sponsor the Foundation Degree fishery students at Sparsholt College to undertake a piece of applied research as part of their course programme.

Fishers Pond Fishery has long been known for producing fabulous carp of all sizes. Recently, John Paton at Fishers Pond Fishery, has been supplementing his feeds with Distillers wheat pellet.

So this year we will be looking at the performance of some of these cheaper alternative diets on the market to see if it make sense to economise of the cost of the feed or perhaps we will see if it is a false economy. I will publish our results later this year.

Last Year’s Results

Last year we looked at how 3 of Coppens’ diets grew our mirror carp. We used their Standard Pellet, their Basic Select carp pellet and their Supreme 16 trout pellet. Each diet was tested in triplicate with 10 fish in each tank.

Jon Clifford took over the running of the research for his dissertation and achieved some pretty impressive and interesting results.

Mirror carp of 19 grams were grown for 8 weeks at 20 degrees C. To ensure the fish received equal amounts of available energy the feed rates were adjusted each week.

Feed rates

Daily Feed Rate %

Standard(S)

3.51

Basic Select (BS)

3.08

Supreme 16(S16)

3

Table of Diet Specifications

Price Euro/kg

Protein %

Lipid %

Meta. energy(MJ/kg)

Standard(S)

0.95

33%

6%

14.1

Basic Select (BS)

1

34%

15%

16.6

Supreme 16(S16)

1.19

46%

16%

17.0

Details of the results are given below and make interesting reading!

Table of Results

Final weight (g)

95% C.I.

Cum. FCR

95% C.I.

Protein Efficiency Ratio

95% C.I.

Specific Growth Rate %

95% C.I.

Standard

38.07

3.9

2.42

0.4

1.26

0.2

1.20

0.1

Basic Select

50.91

4.6

1.45

0.2

2.04

0.3

1.73

0.2

Supreme 16

62.92

16.7

1.16

0.3

1.88

0.4

2.10

0.4

This graph shows the final weights of the fish. The fish on the standard carp diet have grown well and at 38grams average were over twice their original weight of 19 grams. However, the fish on the Trout diet have grown over 3 times their original weight and were already twice a big as the fish grown on the standard diet despite the fact that the fish have all had the same ‘available’ energy.

So the daily growth rate of a carp on the trout diet was an impressive 2.1% . Why was it growing the fish so much faster? The reason for this becomes clearer when you look at the graph below.

The fish on the trout diet were converting the feed at an impressive rate of 1.16:1. Whereas the fish on the standard carp diet only converted the food at 2.42:1. However, note that the fish grown on the higher specification carp diet (Basic Select) were also converting at a respectable 1.45:1.

So the message is clear. If your water temperatures are high enough for the fish to digest efficiently you should be using a higher specification diet to maximise the growth potential. How will this affect your profit? Have a look at the table below.

Food Price Euro/kg

Cum. FCR

Cost of food (£)/kg prod.

Gross Margin (£)/kg

SGR %

Gross margin * daily output

Daily Relative advantage %

Standard

1.08

2.42

2.61

8.39

1.20%

0.101

0%

Basic Select

1.1

1.45

1.59

9.41

1.73%

0.163

61%

Supreme 16

1.35

1.16

1.57

9.43

2.10%

0.198

96%

*1 kg of carp sell for £15 and have other variable costs of £4/kg. Assume Euro : £ exchange is 1 to 1!

The the daily economic advantage of the high spec diet is 96%. I say go for it!